Fischer-tropsch processes and catalysts with promoters

ABSTRACT

A process is disclosed for producing hydrocarbons. The process involves contacting a feed stream comprising hydrogen and carbon monoxide with a catalyst in a reaction zone maintained at conversion-promoting conditions effective to produce an effluent stream comprising hydrocarbons. In accordance with this invention, the catalyst used in the process preferably includes at least cobalt, rhenium, and a promoter selected from the group including boron, phosphorus, potassium, manganese, and vanadium. The catalyst may also comprise a support material selected from the group including silica, titania, titania/alumina, zirconia, alumina, aluminum fluoride, and fluorided aluminas.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is a divisional application of U.S. applicationSer. No. 09/314,811, which claims the benefit of U.S. provisional patentapplication Serial No. 60/086,372, filed May 22, 1998, U.S. provisionalpatent application Serial No. 60/086,405, filed May 22, 1998, and ofU.S. provisional patent application Serial No. 60/097,180, filed Aug.20, 1998, all of which are incorporated herein by reference in theirentirety.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

[0002] Not applicable.

FIELD OF THE INVENTION

[0003] The present invention relates to a process for the preparation ofhydrocarbons from synthesis gas, (i.e., a mixture of carbon monoxide andhydrogen), typically labeled the Fischer-Tropsch process. Particularly,this invention relates to the use of aluminum fluoride or fluoridedalumina supported catalysts containing cobalt and rhenium and at leastone other element selected from boron, phosphorus, potassium, manganeseand vanadium, for the Fischer-Tropsch process.

BACKGROUND OF THE INVENTION

[0004] Large quantities of methane, the main component of natural gas,are available in many areas of the world. Methane can be used as astarting material for the production of hydrocarbons. The conversion ofmethane to hydrocarbons is typically carried out in two steps. In thefirst step methane is reformed with water or partially oxidized withoxygen to produce carbon monoxide and hydrogen (i.e., synthesis gas orsyngas). In a second step, the syngas is converted to hydrocarbons.

[0005] This second step, the preparation of hydrocarbons from synthesisgas is well known in the art and is usually referred to asFischer-Tropsch synthesis, the Fischer-Tropsch process, orFischer-Tropsch reaction(s). Catalysts for use in such synthesis usuallycontain a catalytically active metal of Groups 8, 9, 10 (in the Newnotation of the periodic table of the elements, which is followedthroughout). In particular, iron, cobalt, nickel, and ruthenium havebeen abundantly used as the catalytically active metals. Cobalt andruthenium have been found to be most suitable for catalyzing a processin which synthesis gas is converted to primarily hydrocarbons havingfive or more carbon atoms (i.e., where the C₅ ⁺ selectivity of thecatalyst is high). Additionally, the catalysts often contain one or morepromoters and a support or carrier material. Rhenium is a widely usedpromoter.

[0006] The Fischer-Tropsch reaction involves the catalytic hydrogenationof carbon monoxide to produce a variety of products ranging from methaneto higher aliphatic alcohols. The methanation reaction was firstdescribed in the early 1900's, and the later work by Fischer and Tropschdealing with higher hydrocarbon synthesis was described in the 1920's.

[0007] The Fischer-Tropsch synthesis reactions are highly exothermic andreaction vessels must be designed for adequate heat exchange capacity.Because the feed streams to Fischer-Tropsch reaction vessels are gaseswhile the product streams include liquids, the reaction vessels musthave the ability to continuously produce and remove the desired range ofliquid hydrocarbon products. The process has been considered for theconversion of carbonaceous feedstock, e.g., coal or natural gas, tohigher value liquid fuel or petrochemicals. The first major commercialuse of the Fischer-Tropsch process was in Germany during the 1930's.More than 10,000 B/D (barrels per day) of products were manufacturedwith a cobalt based catalyst in a fixed-bed reactor. This work has beendescribed by Fischer and Pichler in Ger. Pat. No. 731,295 issued Aug. 2,1936.

[0008] Motivated by production of high-grade gasoline from natural gas,research on the possible use of the fluidized bed for Fischer-Tropschsynthesis was conducted in the United States in the mid-1940s. Based onlaboratory results, Hydrocarbon Research, Inc. constructed a dense-phasefluidized bed reactor, the Hydrocol unit, at Carthage, Tex., usingpowdered iron as the catalyst. Due to disappointing levels ofconversion, scale-up problems, and rising natural gas prices, operationsat this plant were suspended in 1957. Research has continued, however,on developing Fischer-Tropsch reactors such as slurry-bubble columns, asdisclosed in U.S Pat. No. 5,348,982 issued Sep. 20, 1994.

[0009] Commercial practice of the Fischer-Tropsch process has continuedfrom 1954 to the present day in South Africa in the SASOL plants. Theseplants use iron-based catalysts, and produce gasoline in relativelyhigh-temperature fluid-bed reactors and wax in relativelylow-temperature fixed-bed reactors.

[0010] Research is likewise continuing on the development of moreefficient Fischer-Tropsch catalyst systems and reaction systems thatincrease the selectivity for high-value hydrocarbons in theFischer-Tropsch product stream. In particular, a number of studiesdescribe the behavior of iron, cobalt or ruthenium based catalysts invarious reactor types, together with the development of catalystcompositions and preparations.

[0011] There are significant differences in the molecular weightdistributions of the hydrocarbon products from Fischer-Tropsch reactionsystems. Product distribution or product selectivity depends heavily onthe type and structure of the catalysts and on the reactor type andoperating conditions. Accordingly, it is highly desirable to maximizethe selectivity of the Fischer-Tropsch synthesis to the production ofhigh-value liquid hydrocarbons, such as hydrocarbons with five or morecarbon atoms per hydrocarbon chain.

[0012] U.S. Pat. No. 4,659,681 issued on Apr. 21, 1987, describes thelaser synthesis of iron based catalyst particles in the 1-100 micronparticle size range for use in a slurry reactor for Fischer-Tropschsynthesis.

[0013] U.S. Pat. No. 4,619,910 issued on Oct. 28, 1986, and U.S. Pat.No. 4,670,472 issued on Jun. 2, 1987, and U.S. Pat. No. 4,681,867 issuedon Jul. 21, 1987, describe a series of catalysts for use in a slurryFischer-Tropsch process in which synthesis gas is selectively convertedto higher hydrocarbons of relatively narrow carbon number range.Reactions of the catalyst with air and water and calcination arespecifically avoided in the catalyst preparation procedure. Thecatalysts are activated in a fixed-bed reactor by reaction with CO+H₂prior to slurrying in the oil phase in the absence of air.

[0014] Catalyst supports for catalysts used in Fischer-Tropsch synthesisof hydrocarbons have typically been oxides (e.g., silica, alumina,titania, zirconia or mixtures thereof, such as silica-alumina). It hasbeen claimed that the Fischer-Tropsch synthesis reaction is only weaklydependent on the chemical identity of the metal oxide support (see E.Iglesia et al. 1993, In: “Computer-Aided Design of Catalysts,” ed. E. R.Becker et al., p. 215, New York, Marcel Dekker, Inc.). The productsprepared by using these catalysts usually have a very wide range ofmolecular weights.

[0015] U.S. Pat. No. 4,477,595 discloses ruthenium on titania as ahydrocarbon synthesis catalyst for the production of C₅ to C₄₀hydrocarbons, with a majority of paraffins in the C₅ to C₂₀ range. U.S.Pat. No. 4,542,122 discloses a cobalt or cobalt-thoria on titania havinga preferred ratio of rutile to anatase, as a hydrocarbon synthesiscatalyst. U.S. Pat. No. 4,088,671 discloses a cobalt-ruthenium catalystwhere the support can be titania but preferably is alumina for economicreasons. U.S. Pat. No. 4,413,064 discloses an alumina supported catalysthaving cobalt, ruthenium and a Group 3 or Group 4 metal oxide, e.g.,thoria. European Patent No. 142,887 discloses a silica supported cobaltcatalyst together with zirconium, titanium, ruthenium and/or chromium.

[0016] International Publication Nos. WO 98/47618 and WO 98/47620disclose the use of rhenium promoters and describe several functionsserved by the rhenium.

[0017] U.S Pat. No. 5,248,701 discloses a copper promotedcobalt-manganese spinel that is said to be useful as a Fischer-Tropschcatalyst with selectivity for olefins and higher paraffins.

[0018] Despite the vast amount of research effort in this field,promoted Fischer-Tropsch catalysts using aluminum fluoride or fluoridedalumina supports are not known in the art. There is still a great needto identify new catalysts for Fischer-Tropsch synthesis, particularlycatalysts that provide high C₅ ⁺ hydrocarbon selectivities to maximizethe value of the hydrocarbons produced and thus the process economics.

SUMMARY OF THE INVENTION

[0019] This invention provides a process for producing hydrocarbons, anda method for preparing the catalyst. The process comprises contacting afeed stream comprising hydrogen and carbon monoxide with a catalyst in areaction zone maintained at conversion-promoting conditions effective toproduce an effluent stream comprising hydrocarbons.

[0020] This invention also provides a process for producinghydrocarbons, comprising contacting a feed stream comprising hydrogenand carbon monoxide with a supported catalyst in a reaction zonemaintained at conversion-promoting conditions effective to produce aneffluent stream comprising hydrocarbons. In accordance with thisinvention, the catalyst used in the process comprises cobalt, optionallyrhenium, and at least one element selected from the group consisting ofboron, phosphorus, potassium, manganese, and vanadium, and one or moresupport materials selected from the group including silica, titania,titania/alumina, zirconia, alumina, aluminum fluoride, and fluoridedaluminas.

DETAILED DESCRIPTION OF THE INVENTION

[0021] The feed gases charged to the process of the invention comprisehydrogen, or a hydrogen source, and carbon monoxide. H₂/CO mixturessuitable as a feedstock for conversion to hydrocarbons according to theprocess of this invention can be obtained from light hydrocarbons suchas methane by means of steam reforming, partial oxidation, or otherprocesses known in the art. Preferably the hydrogen is provided by freehydrogen, although some Fischer-Tropsch catalysts have sufficient watergas shift activity to convert some water to hydrogen for use in theFischer-Tropsch process. It is preferred that the molar ratio ofhydrogen to carbon monoxide in the feed be greater than 0.5:1 (e.g.,from about 0.67 to 2.5). Preferably, the feed gas stream containshydrogen and carbon monoxide in a molar ratio of about 2:1. The feed gasmay also contain carbon dioxide. The feed gas stream should contain alow concentration of compounds or elements that have a deleteriouseffect on the catalyst, such as poisons. For example, the feed gas mayneed to be pre-treated to ensure that it contains low concentrations ofsulfur or nitrogen compounds such as hydrogen sulfide, ammonia andcarbonyl sulfides.

[0022] The feed gas is contacted with the catalyst in a reaction zone.Mechanical arrangements of conventional design may be employed as thereaction zone including, for example, fixed bed, fluidized bed, slurryphase, slurry bubble column, reactive distillation column, or ebullatingbed reactors, among others, may be used. Accordingly, the size andphysical forOm of the catalyst particles may vary depending on thereactor in which they are to be used.

[0023] The active catalyst components used in this invention are carriedor supported on a support selected from the group including silica,titania, titania/alumina, zirconia, alumina, aluminum fluoride, andfluorided alumina, silica, titania, and titania/alumina. Aluminumfluoride supports are defined as at least one aluminum fluoride (e.g.,alpha-AlF₃, beta-AlF₃, delta-AlF₃, eta-AlF₃, gamma-AIF₃, kappa-AlF₃and/or theta-AlF₃). Preferred supports include alumina and aluminumfluoride. Preferred aluminum fluoride supports are aluminum fluoridesthat are primarily alpha-AlF₃ and/or beta-AlF₃.

[0024] Fluorided alumina is defined as a composition comprisingaluminum, oxygen, and fluorine. The fluoride content of the fluoridedalumina can vary over a wide range, from about 0.001% to about 67.8% byweight. Preferred are fluorided aluminas containing from 0.001% to about10% by weight fluorine. The remainder of the fluorided alumina componentwill include aluminum and oxygen. The composition may also contain aminor amount (compared to aluminum) of silicon, titanium, phosphorus,zirconium and/or magnesium.

[0025] The support material comprising fluorided aluminas and/or analuminum fluoride may be prepared by a variety of methods. For example,U.S. Pat. Nos. 4,275,046 and 4,902,838 and 5,243,106 disclose thepreparation of fluorided alumina by the reaction of alumina with avaporizable fluorine-containing fluorinating compound. Suitablefluorinating compounds include HF, CCl₃F, CCl₂F₂, CHClF₂, CH₃CHF₂,CCl₂FCClF₂ and CHF₃. U.S. Pat. No. 5,243,106 discloses the preparationof a high purity AlF₃ from aluminum sec-butoxide and HF.

[0026] Metals can be supported on aluminum fluoride or on fluoridedalumina in a variety of ways. For example, U.S. Pat. No. 4,766,260discloses the preparation of metals such as cobalt on a fluoridedalumina support using impregnation techniques to support the metal. U.S.Pat. No. 5,559,069 discloses the preparation of a multiphase catalystcomposition comprising various metal fluorides including cobalt fluoridehomogeneously dispersed with aluminum fluoride. PCT Int. Publ. No.97/19751 discloses the preparation of multiphase catalyst compositionscomprising metallic ruthenium homogeneously dispersed with various metalfluorides including aluminum fluoride.

[0027] Phases of aluminum fluoride such as eta, beta, theta and kappacan be prepared as described in U.S. Pat. Nos. 5,393,509, 5,417,954, and5,460,795.

[0028] Aluminas that have been treated with fluosilicic acid (H₂SiF₆)such as those described in European Patent Application No. EP 497,436can also be used as a support. The disclosed support comprises fromabout 0.5 to about 10 weight percent of fluorine, from 0.5 to about 5weight percent of silica and from about 85 to about 99 weight percent ofalumina.

[0029] The catalyst contains a catalytically effective amount of cobaltand rhenium. The amount of cobalt and rhenium present in the catalystmay vary widely. Typically, the catalyst comprises from about 1 to 50%by weight (as the metal) of the total supported cobalt and rhenium pertotal weight of catalytic metal and support, preferably from about 1 to30% by weight, and more preferably from about 1 to 25% by weight.Rhenium is added to the support in a concentration sufficient to providea weight ratio of elemental rhenium:elemental cobalt of from about0.001:1 to about 0.25:1, preferably from about 0.001:1 to about 0.05:1(dry basis).

[0030] We have found that higher selectivity and productivity catalystsare produced when a promoter selected from the group consisting ofboron, phosphorus, potassium, manganese and vanadium is added to thecobalt-rhenium catalyst. This is quite surprising because boron andphosphorus are typically considered to be Fischer-Tropsch catalystpoisons. Additionally, and even more surprisingly, the catalysts of thepresent invention exhibit both improved conversion and improvedstability, with long lifetime, relative to prior art Fischer-Tropschcatalysts. The conversion is particularly high in the case of the boronand manganese promoted catalysts of the present invention, and can equalor approach 100%. The amount of promoter is added to the cobalt-rheniumcatalyst in a concentration sufficient to provide a weight ratio ofelemental promoter:elemental cobalt of from about 0.00005:1 to about0.5:1, preferably, from about 0.0005:1 to about 0.01:1 (dry basis).

[0031] The catalysts of the present invention may be prepared by any ofthe methods known to those skilled in the art. By way of illustrationand not limitation, such methods include impregnating the catalyticallyactive compounds or precursors onto a support, extruding one or morecatalytically active compounds or precursors together with supportmaterial to prepare catalyst extrudates, and/or precipitating thecatalytically active compounds or precursors onto a support.Accordingly, the supported catalysts of the present invention may beused in the form of powders, particles, pellets, monoliths, honeycombs,packed beds, foams, and aerogels.

[0032] The most preferred method of preparation may vary among thoseskilled in the art, depending for example on the desired catalystparticle size. Those skilled in the art are able to select the mostsuitable method for a given set of requirements.

[0033] One method of preparing a supported metal catalyst (e.g., asupported cobalt, cobalt/rhenium, or cobalt/rhenium/promoter catalyst)is by incipient wetness impregnation of the support with an aqueoussolution of a soluble metal salt such as nitrate, acetate,acetylacetonate or the like. Another method of preparing a supportedmetal catalyst is by a melt impregnation technique, which involvespreparing the supported metal catalyst from a molten metal salt. Onepreferred method is to impregnate the support with a molten metalnitrate (e.g., Co(NO₃)₂.6H₂O). Alternatively, the support can beimpregnated with a solution of zero valent metal precursor. Onepreferred method is to impregnate the support with a solution of zerovalent cobalt such as Co₂(CO)₈, Co₄(CO)₁₂ or the like in a suitableorganic solvent (e.g., toluene). Suitable rhenium compounds are thecommon water soluble ones, e.g., rhenium heptoxide (Re₂O₇) and ammoniumperrhenate (NH₄ReO₄).

[0034] The impregnated support is dried and reduced with hydrogen or ahydrogen containing gas. The hydrogen reduction step may not benecessary if the catalyst is prepared with zero valent cobalt. Inanother preferred method, the impregnated support is dried, oxidizedwith air or oxygen and reduced in the presence of hydrogen.

[0035] Typically, at least a portion of the metal(s) of the catalyticmetal component (a) of the catalysts of the present invention is presentin a reduced state (i.e., in the metallic state). Therefore, it isnormally advantageous to activate the catalyst prior to use by areduction treatment, in the presence of hydrogen at an elevatedtemperature. Typically, the catalyst is treated with hydrogen at atemperature in the range of from about 75° C. to about 500° C., forabout 0.5 to about 24 hours at a pressure of about 1 to about 75 atm.Pure hydrogen may be used in the reduction treatment, as may a mixtureof hydrogen and an inert gas such as nitrogen, or a mixture of hydrogenand other gases as are known in the art, such as carbon monoxide andcarbon dioxide. Reduction with pure hydrogen and reduction with amixture of hydrogen and carbon monoxide are preferred. The amount ofhydrogen may range from about 1% to about 100% by volume.

[0036] The Fischer-Tropsch process is typically run in a continuousmode. In this mode, the gas hourly space velocity through the reactionzone typically may range from about 100 volumes/hour/volume catalyst(v/hr/v) to about 10,000 v/hr/v, preferably from about 300 v/hr/v toabout 2,000 v/hr/v. The reaction zone temperature is typically in therange from about 160° C. to about 300° C. Preferably, the reaction zoneis operated at conversion promoting conditions at temperatures fromabout 190° C. to about 260° C. The reaction zone pressure is typicallyin the range of about 80 psig (653 kPa) to about 1000 psig (6994 kPa),preferably, from 80 psig (653 kPa) to about 600 psig (4237 kPa), andstill more preferably, from about 140 psig (1066 kPa) to about 400 psig(2858 kPa).

[0037] The products resulting from the process will have a great rangeof molecular weights. Typically, the carbon number range of the producthydrocarbons will start at methane and continue to the limits observableby modern analysis, about 50 to 100 carbons per molecule. The process isparticularly useful for making hydrocarbons having five or more carbonatoms especially when the above-referenced preferred space velocity,temperature and pressure ranges are employed.

[0038] The wide range of hydrocarbons produced in the reaction zone willtypically afford liquid phase products at the reaction zone operatingconditions. Therefore the effluent stream of the reaction zone willoften be a mixed phase stream including liquid and vapor phase products.The effluent stream of the reaction zone may be cooled to effect thecondensation of additional amounts of hydrocarbons and passed into avapor-liquid separation zone separating the liquid and vapor phaseproducts. The vapor phase material may be passed into a second stage ofcooling for recovery of additional hydrocarbons. The liquid phasematerial from the initial vapor-liquid separation zone together with anyliquid from a subsequent separation zone may be fed into a fractionationcolumn. Typically, a stripping column is employed first to remove lighthydrocarbons such as propane and butane. The remaining hydrocarbons maybe passed into a fractionation column where they are separated byboiling point range into products such as naphtha, kerosene and fueloils. Hydrocarbons recovered from the reaction zone and having a boilingpoint above that of the desired products may be passed into conventionalprocessing equipment such as a hydrocracking zone in order to reducetheir molecular weight. The gas phase recovered from the reactor zoneeffluent stream after hydrocarbon recovery may be partially recycled ifit contains a sufficient quantity of hydrogen and/or carbon monoxide.

[0039] Without further elaboration, it is believed that one skilled inthe art can, using the description herein, utilize the present inventionto its fullest extent. The following embodiments are to be construed asillustrative, and not as constraining the scope of the present inventionin any way whatsoever.

EXAMPLES General Procedure for Batch Tests

[0040] Each of the catalyst samples was treated with hydrogen prior touse in the Fischer-Tropsch reaction. The catalyst sample was placed in asmall quartz crucible in a chamber and purged with 500 sccm (8.3×10⁻⁶m³/s) nitrogen at room temperature for 15 minutes. The sample was thenheated under 100 sccm (1.7×10⁻⁶ m³/s) hydrogen at 1° C./minute to 100°C. and held at 100° C. for one hour. The catalysts were then heated at1° C./minute to 400° C. and held at 400° C. for four hours under 100sccm (1.7×10⁻⁶ m³/s) hydrogen. The samples were cooled in hydrogen andpurged with nitrogen before use.

[0041] A 2 mL pressure vessel was heated at either 200° C. or 225° C.under 1000 psig (6994 kPa) of H₂:CO (2:1) and maintained at thattemperature and pressure for 1 hour. In a typical run, roughly 50 mg ofthe reduced catalyst and 1 mL of n-octane was added to the vessel. Afterone hour, the reactor vessel was cooled in ice, vented, and an internalstandard of di-n-butylether was added. The reaction product was analyzedon an HP6890 gas chromatograph. Hydrocarbons in the range of C₁₁-C₄₀were analyzed relative to the internal standard. The lower hydrocarbonswere not analyzed since they are masked by the solvent and are alsovented as the pressure is reduced.

[0042] A C₁₁ ⁺ Productivity (g C₁₁ ⁺/hour/kg catalyst) was calculatedbased on the integrated production of the C₁₁-C₄₀ hydrocarbons per kg ofcatalyst per hour. The logarithm of the weight fraction for each carbonnumber ln(W_(n)/n) was plotted as the ordinate vs. number of carbonatoms in (W_(n)/n) as the abscissa. From the slope, a value of alpha wasobtained. Some runs displayed a double alpha as shown in the tables. Theresults of runs over a variety of catalysts at 200° C. are shown inTable 1.

Catalyst Preparation Example 1

[0043] Re₂O₇ (0.0650 g) and B₂O₃ (0.0016 g) were dissolved in a smallamount of water, add to molten Co(NO₃)₂.6H₂O (4.9384 g) and mixed well.Engelhard fluorided alumina (4352-3.95 g) was slurried into thissolution. The slurry was dried at 80° C. The solids were removed fromthe oven and exposed to air to absorb moisture. The solids were thendried again at 80° C. followed by heating the solids at 0.5° C. perminute to 350° C. and maintaining the solids at this temperature for 18minutes. The solids were then reduced in hydrogen flow at 450° C. for 6hours. The material was cooled and flushed with nitrogen overnight andthen sealed for transport into an inert atmosphere glove box. Therecovered catalyst was bottled and sealed for storage inside the glovebox until Fischer-Tropsch testing could be completed. The catalyst had anominal composition of 20%Co/1.0%Re/0.01%B/Al₂O₃(F). This catalyst wasalso used in Example 17.

Example 2

[0044] The same procedure and materials as used in example 1 were used,except that 0.0080 g of B₂O₃ was used. The catalyst had a nominalcomposition of 20%Co/1.0%Re/0.05%B/Al₂O₃(F). This catalyst was also usedin Example 18.

Example 3

[0045] The same procedure and materials as used in example 1 were used,except that 0.0161 g of B₂O₃ was used. The catalyst had a nominalcomposition of 20%Co/1.0%Re/0.1%B/Al₂O₃(F). This catalyst was also usedin Example 19.

Example 4

[0046] The same procedure and materials as used in example 1 were used,except that Al₂O₃ (Chimet, 3.9500 g) and P₂O₅ (0.0011 g) was used. Thecatalyst had a nominal composition of 20%Co/1.0%Re/0.01%P/Al₂O₃. Thiscatalyst was also used in Example 20.

Example 5

[0047] The same procedure and materials as used in example 4 were used,except that 0.0055 g of P₂O₅ was used. The catalyst had a nominalcomposition of 20%Co/1.0%Re/0.05%P/Al₂O₃. This catalyst was also used inExample 21.

Example 6

[0048] The same procedure and materials as used in example 4 were used,except that 0.0110 g of P₂O₅ was used. The catalyst had a nominalcomposition of 20%Co/1.0%Re/0.1%P/Al₂O₃. This catalyst was also used inExample 22.

Example 7

[0049] The same procedure and materials as used in example 4 were used,except that 3.9250 g of Al₂O₃ and 0.0550 g of P₂O₅ were used. Thecatalyst had a nominal composition of 20%Co/1.0%Re/0.5%P/Al₂O₃. Thiscatalyst was also used in Example 23.

Example 8

[0050] The same procedure and materials as used in example 7 were used,except that 3.9000 g of Al₂O₃ and 0.1100 g of P₂O₅ were used. Thecatalyst had a nominal composition of 20%Co/1.0%Re/1.0%P/Al₂O₃. Thiscatalyst was also used in Example 24.

Example 9

[0051] The same procedure and materials as used in example 1 were used,except that Al₂O₃ (Chimet, 3.9500 g) and B₂O₃ (0.0161 g) were used. Thecatalyst had a nominal composition of 20%Co/1.0%Re/0.1%B/Al₂O₃. Thiscatalyst was also used in Example 25.

Example 10

[0052] The same procedure and materials as used in example 1 were used,except that Al₂O₃ (Chimet, 3.9250 g) and B₂O₃ (0.0805 g) were used. Thecatalyst had a nominal composition of 20%Co/1.0%Re/0.5%B/Al₂O₃. Thiscatalyst was also used in Example 26.

Example 11

[0053] The same procedure and materials as used in example 1 were used,except that Al₂O₃ (Chimet, 3.925 g) NH₄ReO₄ (0.1080 g) and KNO₃ (0.0065g) were used. The catalyst had a nominal composition of20%Co/1.5%Re/0.05%K/Al₂O₃.

Example 12

[0054] The same procedure and materials as used in example 1 were used,except that Al₂O₃ (Chimet, 3.8975 g), NH₄ReO₄ (0.1440 g) and Mn(NO₃)₂(0.0160 g) were used. The catalyst had a nominal composition of20%Co/2.0%Re/0.1%Mn/Al₂O₃. This catalyst was also used in Example 27.

Example 13

[0055] The same procedure and materials as used in example 1 were used,except that Al₂O₃ (Chimet, 3.8925 g), NH4ReO₄ (0.1440 g) and Mn(NO₃)₂(0.0480 g) were used. The catalyst had a nominal composition of20%Co/2.0%Re/0.3%Mn/Al₂O₃. This catalyst was also used in Example 28.

Example 14

[0056] The same procedure and materials as used in example 1 were used,except that Al₂O₃ (Chimet, 3.8750 g), NH₄ReO₄ (0.1440 g) and Mn(NO₃)₂(0.1610 g) were used. The catalyst had a nominal composition of20%Co/2.0%Re/1.0%Mn/Al₂O₃. This catalyst was also used in Example 29.

Example 15

[0057] The same procedure and materials as used in example 1 were used,except that Al₂O₃ (Chimet, 3.975 g), Re₂O₇ (0.0650 g) and NH₄VO₃ (0.0287g) were used. The catalyst had a nominal composition of20%Co/1.0%Re/0.25%V/Al₂O₃.

Example 16

[0058] The same procedure and materials as used in example 1 were used,except that Al₂O₃ (Chimet, 3.925 g), Re₂O₇ (0.0650 g) and NH₄VO₃ (0.0574g) were used. The catalyst had a nominal composition of20%Co/1.0%Re/0.5%V/Al₂O₃. TABLE 1 Ex. No. Catalyst C₁₁+ ProductivityAlpha 1 20%Co/1.0%Re/0.01%B/Al₂O₃(F) 753 0.89 220%Co/1.0%Re/0.05%B/Al₂O₃(F) 747 0.88 3 20%Co/1.0%Re/0.1%B/Al₂O₃(F) 7140.88 4 20%Co/1.0%Re/0.01%P/Al₂O₃ 866 0.9 5 20%Co/1.0%Re/0.05%P/Al₂O₃ 7160.87 6 20%Co/1.0%Re/0.1%P/Al₂O₃ 779 0.89 7 20%Co/1.0%Re/0.5%P/Al₂O₃ 7160.9 8 20%Co/1.0%Re/1%P/Al₂O₃ 676 0.89 9 20%Co/1.0%Re/0.1%B/Al₂O₃ 8190.89 10 20%Co/1.0%Re/0.5%B/Al₂O₃ 957 0.89 11 20%Co/1.0%Re/0.05%K/Al₂O₃741 0.89 12 20%Co/2.0%Re/0.1%Mn/Al₂O₃ 832 0.89 1320%Co/2.0%Re/0.3%Mn/Al₂O₃ 1000  0.9 14 20%Co/2.0%Re/1%Mn/Al₂O₃ 920 0.8915 20%Co/1.0%Re/0.25%V/Al₂O₃ 963 0.88 16 20%Co/1.0%Re/0.5%V/Al₂O₃ 9230.9

[0059] General Procedure for Continuous Tests

[0060] The catalyst testing unit was composed of a syngas feed system, atubular reactor, which had a set of wax and cold traps, back pressureregulators, and three gas chromatographs (one on-line and two off-line).

[0061] The carbon monoxide was purified before being fed to the reactorover a 22% lead oxide on alumina catalyst placed in a trap to remove anyiron carbonyls present. The individual gases or mixtures of the gaseswere mixed in a 300 mL vessel filled with glass beads before enteringthe supply manifold feeding the reactor.

[0062] The reactor was made of ⅜ in. (0.95 cm) O.D. by ¼ in. (0.63 cm)I.D. stainless steel tubing. The length of the reactor tubing was 14 in.(35.6 cm). The actual length of the catalyst bed was 10 in. (25.4 cm)with 2 in. (5.1 cm) of 25/30 mesh (0.71/0.59 mm) glass beads and glasswool at the inlet and outlet of the reactor.

[0063] The wax and cold traps were made of 75 mL pressure cylinders. Thewax traps were set at 140° C. while the cold traps were set at 0° C. Thereactor had two wax traps in parallel followed by two cold traps inparallel. At any given time products from the reactor flowed through onewax and one cold trap in series. Following a material balance period,the hot and cold traps used were switched to the other set in parallel,if needed. The wax traps collected a heavy hydrocarbon productdistribution (usually between C₆ and above) while the cold trapscollected a lighter hydrocarbon product distribution (usually between C₃and C₂₀). Water, a major product of the Fischer-Tropsch process wascollected in both the traps.

[0064] General Analytical Procedure

[0065] The uncondensed gaseous products from the reactors were analyzedusing a common on-line HP Refinery Gas Analyzer. The Refinery GasAnalyzer was equipped with two thermal conductivity detectors andmeasured the concentrations of CO, H₂, N₂, CO₂, CH₄, C₂ to C₅alkenes/alkanes/isomers and water in the uncondensed reactor products.The products from each of the hot and cold traps were separated into anaqueous and an organic phase. The organic phase from the hot trap wasusually solid at room temperature. A portion of this solid product wasdissolved in carbon disulfide before analysis. The organic phase fromthe cold trap was usually liquid at room temperature and was analyzed asobtained. The aqueous phase from the two traps was combined and analyzedfor alcohols and other oxygenates. Two off-line gas chromatographsequipped with flame ionization detectors were used for the analysis ofthe organic and aqueous phases collected from the wax and cold traps.

[0066] Catalyst Testing Procedure

[0067] Catalyst (3 g) to be tested was mixed with 4 grams of 25/30 mesh(0.71/0.59 mm) and 4 grams of 2 mm glass beads. The 14 in. (35.6 cm)tubular reactor was first loaded with 25/30 mesh (0.71/0.59 mm) glassbeads so as to occupy 2 in. (5.1 cm) length of the reactor. Thecatalyst/glass bead mixture was then loaded and occupied 10 in. (25.4cm) of the reactor length. The remaining 2 in. (5.1 cm) of reactorlength was once again filled with 25/30 mesh (0.71/0.59 mm) glass beads.Both ends of the reactor were plugged with glass wool.

[0068] Catalyst activation was subsequently carried out using thefollowing procedure. The reactor was heated to 120° C. under nitrogenflow (100 cc/min and 40 psig (377 kPa)) at a rate of 1.5° C./min. Thereactor was maintained at 120° C. under these conditions for two hoursfor drying of the catalyst. At the end of the drying period, the flowwas switched from nitrogen to hydrogen. The reactor was heated underhydrogen flow (100 cc/min and 40 psig (377 kPa)) at a rate of 1.4°C./min. to 350° C. The reactor was maintained at 350° C. under theseconditions for sixteen hours for catalyst reduction. At the end of thereduction period, the flow was switched back to nitrogen and the reactorcooled to reaction temperature (usually 220° C.).

[0069] The reactor was pressurized to the desired reaction pressure andcooled to the desired reaction temperature. Syngas, with a 2:1 H₂/COratio was then fed to the reactor when reaction conditions were reached.

[0070] The first material balance period started at about four hoursafter the start of the reaction. A material balance period lasted forbetween 16 to 24 hours. During the material balance period, data wascollected for feed syngas and exit uncondensed gas flow rates andcompositions, weights and compositions of aqueous and organic phasescollected in the wax and cold traps, and reaction conditions such astemperature and pressure. The information collected was then analyzed toget a total as well as individual carbon, hydrogen and oxygen materialbalances. From this information, CO Conversion (%), Selectivity/Alphaplot for all (C₁ to C₄₀) of the hydrocarbon products, C₅+ Productivity(g/hr/kg cat), weight percent CH₄ in hydrocarbon products (%) and otherdesired reactor outputs were calculated.

[0071] The results obtained from the continuous-flow Fischer-Tropschcatalyst testing unit is shown in Tables 2 and 3.

[0072] Table 2 lists the catalyst composition, CO Conversion (%), Alphavalue from the Anderson-Shultz-Flory plot of the hydrocarbon productdistribution, C₅+ Productivity (g C₅+/hour/kgcatalyst) and weightpercent methane in the total hydrocarbon product (%).

[0073] The temperature was 220° C., the pressure was between 340 psig(2445 kPa) to 362 (2597 kPa) and the space velocity was 2 NL/hour/g.cat. for all the examples in Table 2. TABLE 2 Ex- am- ple % % No.Catalyst Conv. alpha C₅+ C₁ 17 20%Co/1.0%Re/0.01%B/Al₂O₃(F) 86 0.85 22417.2 18 20%Co/1.0%Re/0.05%B/Al₂O₃(F) 65 0.88 158 18 1920%Co/1.0%Re/0.1%B/Al₂O₃(F) 92 0.88 289 8.4 20 20%Co/1.0%Re/0.01%P/Al₂O₃95 0.88 276 14.1 21 20%Co/1.0%Re/0.05%P/Al₂O₃ 93 0.9 261 13.9 2220%Co/1.0%Re/0.1%P/Al₂O₃ 87 0.9 276 11.0 23 20%Co/1.0%Re/0.5%P/Al₂O₃ 830.9 170 18 24 20%Co/1.0%Re/1%P/Al₂O₃ 93 0.91 291 10.6 2520%Co/1.0%Re/0.1%B/Al₂O₃ 90 0.9 269 10.2 26 20%Co/1.0%Re/0.5%B/Al₂O₃ 990.9 281 13.6 27 20%Co/1.0%Re/0.1%Mn/Al₂O₃ 97 0.9 263 9.6 2820%Co/2.0%Re/0.3%Mn/Al₂O₃ 92 0.91 365 10.9 29 20%Co/2.0%Re/1%Mn/Al₂O₃100  0.9 272 16.6

[0074] Table 3 lists the catalyst composition, CO Conversion (%), Alphavalue from the Anderson-Shultz-Flory plot of the hydrocarbon productdistribution, C₅+ Productivity (g C₅+/hour/kgcatalyst) and weightpercent methane in the total hydrocarbon product (%) for examplesillustrating the extended lifetimes of the catalysts of the presentinvention. Example 30 is a comparative example showing results for asupported cobalt/rhenium catalyst without the promoters of the presentinvention.

[0075] Examples 31-34 show the superior results obtained using thecatalysts of the present invention after approximately 160 hours ofcontinuous operation. The temperature was 220° C., the pressure wasbetween 340 psig (2445 kPa) to 362 (2597 kPa) and the space velocity was2 NL/hour/g. cat. for all the examples in Table 3, i.e., the sameconditions as for examples 17-29, except for the length of operation.TABLE 3 Example % % No. Catalyst Conv. alpha C₅+ C₁ 30 20%Co/1%Re/Al₂O₃77 0.88 217 12 31 20%Co/1%Re/0.5%B/Al₂O₃ 98 0.91 277 13 3220%Co/1%Re/0.1%B/Al₂O₃ 87 0.90 267 11 33 20%Co/2%Re/0.1%Mn/Al₂O₃ 97 0.90263 10 34 20%Co/1%Re/1%Mn/Al₂O₃ 100  0.91 272 16

[0076] While a preferred embodiment of the present invention has beenshown and described, it will be understood that variations can be madeto the preferred embodiment without departing from the scope of, andwhich are equivalent to, the present invention. For example, thestructure and composition of the catalyst can be modified and theprocess steps can be varied.

[0077] The complete disclosures of all patents, patent documents, andpublications cited herein are incorporated by reference in theirentirety. U.S. patent application Ser. No. 09/314,921, entitledFischer-Tropsch Processes and Catalysts Using Fluorided Supports, filedMay 19, 1999, and U.S. patent application Ser. No. 09/314,920, entitledFischer-Tropsch Processes and Catalysts Using Fluorided Alumina Supportsfiled May 19, 1999, are incorporated by reference in their entirety.

[0078] The foregoing detailed description and examples have been givenfor clarity of understanding only. No unnecessary limitations are to beunderstood therefrom. The invention is not limited to the exact detailsshown and described, for variations obvious to one skilled in the artwill be included within the invention by the claims.

We claim:
 1. A process for producing hydrocarbons, comprising contactinga feed stream comprising hydrogen and carbon monoxide with a catalyst ina reaction zone maintained at conversion-promoting conditions effectiveto produce an effluent stream comprising C₅ and higher hydrocarbons;said catalyst comprising: cobalt; a promoter selected from the groupconsisting of boron and phosphorous, wherein the promoter is effectiveto enhance the selectivity of the catalyst for producing the C₅ andhigher hydrocarbons, wherein the weight ratio of elemental promoter toelemental cobalt is between about 0.0005:1 and 0.5:1; and an aluminasupport.
 2. The process of claim 1 wherein the catalyst furthercomprises rhenium.
 3. The process of claim 1 wherein the promotercomprises boron.
 4. The process of claim 3 wherein the catalyst furthercomprises rhenium.
 5. The process of claim 1 wherein the promotercomprises phosphorous.
 6. The process of claim 5 wherein the catalystfurther comprises rhenium.
 7. A process for producing hydrocarbons,comprising contacting a feed stream comprising hydrogen and carbonmonoxide with a catalyst in a reaction zone maintained atconversion-promoting conditions effective to produce an effluent streamcomprising C₅ and higher hydrocarbons; said catalyst comprising: cobalt;rhenium; a promoter selected from the group consisting of boron andphosphorous, wherein the promoter is effective to enhance theselectivity of the catalyst for producing the C₅ and higherhydrocarbons, wherein the weight ratio of elemental promoter toelemental cobalt is between about 0.0005:1 and 0.5:1; and an aluminasupport.
 8. The process of claim 7 wherein the promoter comprises boron.9. The process of claim 7 wherein the promoter comprises phosphorous.10. A process for producing hydrocarbons, comprising contacting a feedstream comprising hydrogen and carbon monoxide with a catalyst in areaction zone maintained at conversion-promoting conditions effective toproduce an effluent stream comprising C₅ and higher hydrocarbons; saidcatalyst comprising: cobalt; a promoter selected from the groupconsisting of boron and phosphorus, wherein the weight ratio ofelemental promoter to elemental cobalt is between about 0.0005:1 and0.5:1; and a support selected from the group consisting of silica,titania, zirconia, alumina, and combinations thereof; wherein thecatalyst is selective to the C₅ and higher hydrocarbons such that underthe conversion-promoting conditions a is at least about 0.90.
 11. Theprocess of claim 10 wherein the promoter comprises boron.
 12. Theprocess of claim 10 wherein the promoter comprises phosphorous.
 13. Theprocess of claim 10 wherein the support comprises alumina.
 14. Theprocess of claim 13 wherein the promoter comprises boron.
 15. Theprocess of claim 13 wherein the promoter comprises phosphorous.
 16. Theprocess of claim 10 wherein the support comprises silica.
 17. Theprocess of claim 16 wherein the promoter comprises boron.
 18. Theprocess of claim 16 wherein the promoter comprises phosphorous.
 19. Theprocess of claim 10 wherein the support comprises titania.
 20. Theprocess of claim 19 wherein the promoter comprises boron.
 21. Theprocess of claim 19 wherein the promoter comprises phosphorous.
 22. Theprocess of claim 10 wherein the support comprises zirconia.
 23. Theprocess of claim 22 wherein the promoter comprises boron.
 24. Theprocess of claim 22 wherein the promoter comprises phosphorous.